Bike Yoke Seat Post Service Parts. Features: Service kit includes wiper, lower bushing, foam ring and 6 brass keyway pins YB-2122 and YB-2123 include lower tube, upper stanchion bushing and wiper Note on lower tubes: diameter can be changed between 30.9 and 31.6mm but NOT 34.9mm. Length must stay the same as original 3rd party web sales (eBay, Amazon, etc.) are strictly prohibited by the manufacturer Specs: Model: Revive Description: O-ring kit #1